Liquid phase conversion apparatus



Feb 23, 1955 s. R. STILES ETAL LIQUID PHASE CONVERSION APPARATUS 2 Sheets-$heet l Filed Feb, 19, 1960 N s O SMTK Y RRC E OT UA N TSBL R T N .RB o N MRM. T E NL M/n .m |ES w MMH AAO SJJ Feb. 23, 1965 s. R. sTlLEs HAL 3,170,759

LIQUID PHASE CONVERSION APPARATUS mea Feb. 1s. 1960 2 sheets-sheet 2 FIG.4

. 47 INVENToRs i SAMUEL R.s'r|| Es JAMES wARBuRToN l BY l-IFORNEY GENT This invention relates to an apparatus for carrying out liquid phase reactions with a liquid catalyst Which is immiscible with the reactants. lt/iore'particularly, the invention relates to an apparatus for carrying out liquid phase reactions of hydrocarbons in the presence of an acid catalyst which is immiscible with the hydrocarbon reactants and products. Still more particularly, the invention relates to an apparatus for carrying out liquid phase alkylation of hydrocarbons in the presence of an acid catalyst such as sulfuric acid.

This application is `a continuation-in-part of prior copending application Serial No. 387,118, filed October 20, 1953, in the names of Samuel R. Stiles, James Warburton and lohn M. Black and Patent No. 2,927,009.

ln carrying out liquid phase reactions in the presence of a liquid catalyst which is immiscible with the reactants, it is necessary to secure intimate mixing of the catalyst and the reactants to thereby form and maintain an emulsion in which either the reactants or the catalyst constitutes the continuous phase. in the alkylation of hydrocarbons, which will bereferred to as illustrative of the reactions to which the present invention is applicable, it is necessary to eiiect intimate mixing of the hydrocarbon reactants and the acid catalyst to obtain the benelits of the catalytic action of the acid catalyst; the degree of mixing of the hydrocarbons and acid is an important factor in determining the rate of conversion and the overall efficiency of the operation. ln the alkylation of isoparatiin hydrocarbons with olefin hydrocarbons in the presence of sulfuric acid, referring to the alkylation of isobutane With butenes and/ or propylenes as an example, apparently the olefin hydrocarbons are absorbed by the sulfuric acid while the isoparain hydrocarbons present remain in a separated phase as droplets. Alhylation reactions take place atthe surface of the droplets forming the discontinuous phase of the emulsion. The degree of mixing of the emulsion and the resulting dispersion of the isobutane droplets in the acid phase of the emulsion have an important effect on the rate at Which the reaction occurs at the surface of the isobutane droplets. Such a process is operated 'in the prior practice with a view to forming and maintaining a proper body of emulsion so as to assure high overall eiciency. Ordinarily a plurality of series arranged communicating reaction zones are used, into the first of which the acid and the bulk of the 'isobutane are introduced for series flow through the zones While the olefin feed is supplied in parallel streams to the respective reaction zones and emulsilied by appropriate mixing means therein. The overiiow from one reaction zone passes to the next reaction zone; from the last reaction Zone the product overiiow passes to the product-acid separation section. The mixing means employed in the reaction zones ordinarily have greater capacity than required to handle the acid and reactants supplied to the respective zones so that recirculation of materials in the respective zones takes place. Since the zones contain materials Vof different densities,l stratication can and does take place. No eiective provision is made for forcing the lighter material down to the inlet of the mixing means. Also, since the upper end of the zones are in open communication, lighter materials can flow arent from any one zone to the product separation section lice without reaching the mixing means of any subsequent zones.

Concurrently with the alkylation reaction, Ythere is a condensation reaction of the olefin hydrocarbons in the sulfuric acid which may be termed hydropolymerization. The condensation products of this reaction are undesirable Vas they reduce the yield of desired products,

accumulate in the acid phase and in the emulsion, and impair the catalytic activity of the acid. The hydropolymerization reaction rate increases with the concentration of the olefin hydrocarbon reactants and the reaction temperature. To improve the eliiciency, both with regard to the alkylate product and the sulfuric acid employed, the alkylation reaction is usually carried out at comparatively low temperatures and at low concentrations of olen hydrocarbon reactants. Thus it is important to maintain in the reaction zone a relatively high concentration of isobutane and as high a ratio of isobutane to olefin reactants as is practicable. To this end an isobutane to olefin feed rate ratio of about 6-10z1 and higher is commonly employed.

it has been found in accordance with the present invention, that the reaction between the isoparatiin hydrocarbons and the olefin hydrocarbons is driven preponderantly in the direction of the alkylation reaction and the undesired products, due to the hydropolyrnerization reaction, reduced to a minimum if a high isoparain-.olefin ratio is maintained in the region of introduction and intermixing of the olefin hydrocarbon into the isoparalin hydrocarbon-acid emulsion, isoparaiiin hydrocarbonolefin ratios in the introduction and intermixing region as low as 200:1 will give important improvements in the results, but the best results are obtained With ratios in the order of 400:1 and higher.

it is an object of this invention to provide an apparatus for effecting liquid phase alkylation of isoparaiiin hydrocarbons with oleiin hydrocarbons in the presence of an acid catalyst in which the acid catalyst and the isoparafiin hydrocarbon reactants are progressed in series flow through a plurality of reaction zones, while the olefin hydrocarbon reactants are supplied in parallel iiow to the plurality of reaction zones to be lintimately intermixed thereat substantially as supplied with the isoparaiiin hydrocarbon and the acid catalyst iiowing through the respective reaction zones, the series flow of the isoparaiiin hydrocarbon and the acid catalyst being from the bottom to the top of a respective zone and from thence to the bottom of the next zone, the mixing means being located at the bottom of each of said zones so that no material can pass through any one of said zones without passing through the respective mixing means and traversing the full length of said Zone; said mixing means furthermore inducing a sufficiently high iiow rate in the region of olefin hydrocarbon introduction to establish thereat a desired high isoparaiiin hydrocarbon-olefin hydrocarbon ratio.

It is also an object of this invention to provide an apparatns for effecting liquid phase alkylation of isoparain hydrocarbons in which the acid catalyst and the isoparaliin hydrocarbon reactants are progressed in series yflow through a plurality of mixing and reaction Zones, while 'the olefin hydrocarbon is supplied in parallel ilow to each of said zones; said mixing zones being separate and maintained at pressures suiiicient for evaporation of hydrocarbon supplied tothe feed for auto-refrigeration of said reaction zones.

It is an object of this invention to provide an apparatus for reacting hydrocarbons in the liquid phase.

Another object of this invention is to provide an apparatus for reacting hydrocarbons in an immiscible liquid mixture.

Still another object of this invention is to provide an apparatus for' .reacting an olefin with a high excess of alkylatable hydrocarbon.

Another object is to provide an apparatus for presenting a high molar excess of isoparaflin at the point of contact with olefin in an alkylat-ion reaction.

Other .objects and advantages of the present invention will become apparent in thefollowing description and disclosure.

The invention will be particularly described with refer-y ence to the accompanying drawings which illustrate the process by reference to embodiments of the apparatus of the invention; -It is to be understood, however, the inven tion is not limited by reference to the specific modifications illustrated by the drawings ybut is capable of 'other modiiication within the scope-fof the invention.

In the drawings,

FIGURE l is a side view partly` in sectionv illustratingv one embodiment of the apparatus of the' invention;

FIGURES 2 and 3 are sectional views of theapparatus of FIGURE l taken on lines 2-2 and l3 3 respectively; FIGURE 4 is an enlarged view ypartly in section of the mixing'device employed;

FIGURE 5 is a sectional viewtaken online 5 5 of FIGURE 4; and

FIGURE 6 is a diagrammaticview of the apparatus set up for carrying'out the novel process of the invention.

Referring to FIGURE 1,-the reactor 10 may be ofany convenient shape and size but ispreferably in the form of a closed ended cylindrical or approximately cylindrical tankvas shown. The reactor-10 is divided by means of a bafflefor dellector plate 13 into a'reaction zone 11 and a settling zone 12. The reaction zone 11 is conveniently of approximately the same volume as the settling zone 12 but this ratio is subject to widevariation.

The reaction zone 11 is divided into an entrance section 14 and a plurality of mixing sections, three mixing sections 15, 16and .17 being included in the reactor 10 shown but two, or more than three, may be employed as operating conditions require. The entrance section 14 is at one end of the reactor 10 and is defined by the dished head 18 and the circular partition 19. The partition 19, as shown in FIGURE 2, has a bottom -section thereof removed to'provide a port 20 through which material ink the section 14 may pass for entrance into the bottom of the mixing sectionrlS. The periphery of the partition 19 is united, as by Welding, to the walls of the reactor 10 and may have stiening and reinforcing means united thereto, as for instance the rectangular bars 21 which are welded to either or both sides of the partition 19.. Mixing section is defined by the cylindrical walls.

of the reactor 10'and has one end closed by the partition 19 and the other endy by the partition 19'. The weir partition 22 is provided adjacent the partition 19 As shown in FIGURE 3, the partition 22 vis likewise circular but has a much larger section removed from its top land is arrangedto forma Weir which establishes the material level in the mixing chamber 15 and thus controls the out- Aflow of materials therefrom; If desired a weir n-otch,-not

shown,fmay be formed in the top of the partition 22 for more accurate material level control. The peripheryv of partition 22 is likewise united, as by welding,to Athe walls of the reactor 10 and may also have stitfening and reinforcing means united thereto, asfor instance the rectangular bars 23 which arewelded to either or both sides of the partition 22. The bar's21 'and 23 may also be usedas a spacing means as will be explained hereinafter. Arectangular plate 24 having a hole 25 thereinhas one end united to the bottom edge of the partition 19 and its sidesunited to the cylindrical wall vofthereactor 10, as by welding, to provide a passageway 26 for flow of material from the bottom of theentrance chamber 14 to substantially the middle region of the bottom of the mixing section 15. The hole 25 may be .circular or rectangular, as preferred. A small plate 27 in the form of a section of a circular disc is united to the walls of theireactor the end of the passageway 26 so that all the material thatA 10 and tothe end of the rectangular ,plate 24r to close enters the .port 20 can only passinto the mixing chamber 15 through the hole 25. lf deemed necessary a small hole, not shown, maybe drilled through the plate27 adjacent the bottom thereof for drainage purposes, otherwise no holes or ports are provided in any of the partition members mentioned. v Y

The construction of the mixing section 16 is substantially identical to that of the section 15, the correspondingy parts of the section 16 arev designated by .primed numerals. The material fromy the mixing. section 15 overflows the top edge of the partition 22, .then ows down through the downow passageway 28, formed between the partitions 22 and 19 to enter'the port 20. The bars 21. and 23 can be made of such a width that the exposed edges thereof bear against the respective opposed partition 19 or 22 and thus maintain .the'spacing between the partitions 19 and22. The mixing section 17 is similar to the section 15 and the corresponding parts thereof have been vdesignated by double primed numerals. The mixing section 17 diifersfromthe mixing sections 15 and 16 primarily in that the downstream endthereof is defined by thercoalizer partition 29 and the deiiector plateY 13 and in that it is in open communication at its top with the settling l.

`with a suitable .packing such as carbon Raschg rings, or crushed siliceous rock whichis inert to the reactants.y

The partition 31 is solid, is substantially theV same as and corresponds to the weir partitions 22 and 22 and establishes the liquid level inthe mixing section 17f. Thepartition 32i's perforated. 1

' Each of the mixing sections 15, 16 and 17 has a mixer provided therein. The mixers 35, 35(61) and 35(1)) are identical in construction so that the description of one of them, the mixer 35, will sutlice for all.

in a circular opening 36 formed in the top of the section'15 andwith. its lower inlet end 33 spaced from the plate 24. and overlying the hole therein. hole 25 is smaller than the inlet of the mixer 35., The` relativeV areas of the linlet of the mixer and the hole 25 and the spacing of said inlet from the plate 24' are so proportioned and adjusted that all the material supplied. to the hole 25 enter-.s said inlet while permitting Y entrance of desired quantities of material through the "space between the yhole 25 'and said inlet. To this kend also, thehole- 25 may have an upwardlyY extending rim or lip united to its periphery (not shown). The walls of the opening 36 are built up to form a ange 37 appropriate size to .support themixer 35 while in operation.

stance by a circular series of bolts, is a cylindrical shell 39 of a diameter to iit loosely within :the opening 36.v

cular series of tubes 41 extending upwardly therefrom.

lAn impeller housing 42 is'positioned beneath the tube.

sheets-i).4 The shell 39, the tube sheet and the impeller housing 42 are fastened ,together intoa unit` by vmeans of a .circular series of studs which enter tapped The mixer 35, shown in detail in FIGURES 4 and 5, is mounted The.

The mixer 35 is suspended from an annular. flange ring 38 whose outer peripheral portion rests on'. the face of the'iiange 37 and is fastened thereto by. aV Vcircular series of bolts.y Extending downward fromV the flange ring 3S -and fastened rigidly thereto, as Vfor in.

holes in a flange at the lower end of the shell 319 and carry suitable nuts threaded thereon which bear against a flange formed at the periphery of the impeller housing 42. The housing 42 is preferably formed as a casting and includes internal deflector webs 43 connecting the housing i2 to a bearing supporting structure 44 which is hollow at its upper end and is provided thereat with ports 45. A suitable impeller 45 provided with blades 47, is mounted on the central shaft 4S which is journaled in the structure 44 and extends vertically therethrough.

The central opening of the flange ring 355 is covered by the peripheral ange of the hollow member 49, said peripheral iiange and the ange ring 38 being united by a circular series of bolts as shown. The hollow member 49 is conical in shape and includes webs which support the bearing structure 5t? for the upper end oi the shaft 43. A nozzle construction Si. is provided for supplying one of the reactants to the hollow of the member 49. A vertical tubular member SZ surrounds the shaft 48 and connects the hollow of the member i9 to the hollow upper end of the bearing support structure 44 so that the reactant that is introduced through the nozzle 51 may ilow from the hollow ot the member d'2* through the tubular member 52 into the hollow of the structure 44 to be discharged through the ports 4S into the outlet of the impeller housing 42. As an alternative construction, the ports 45 may be eliminated and in their stead a transverse bore may be provided in each of the deflector webs 43, said transverse bores being placed in communication throughA suitable bores with the hollow upper end of the member 4d. The reactant may llow out of the transverse bores through a plurality of small holes in the face of the deiiector webs 43 or through holes in the slip stream end or" the webs 43 (this alternative construction is not shown). As another alternative, perforated and horizontally disposed tubular members can be mounted into ports i5 for reactant dispersion in a plurality or small streams across the flow path of upwardly moving liquid. In addition, the vertical tubular member 52, instead of enclosing shaft dit, can be vertically disposed immediately adjacent the inner wall of shell 39. ln both instances, the perorated tubular members, horizontally disposed in said mixer are supplied with reactant from the vertical tubular member 52 from a point centrally located in the mixer or from a point adjacent the shell inner Wall of the mixer or from any other convenient location entering the shell of the mixer.

The upper end of each of said tubes 41 terminates a substantial distance below the flange ring 33 so that sutiicient space is provided for the reversal of direction of iiow of the material propelled Ithrough the tubes il by the impeller Lid. After the iiow reversal just menioned, the propelled material flows downwardly in the space between the tubes 41, the tubular member 52 and shell 39 to exit from the series of elongated holes 53 located adjacent the bottom end of the shell 39. A series of comparatively small gas vent holes are provided adjacent the top end of the shell 39 to prevent gas accumulation in the flow reversing space between the upper end ot' the tubes 41 and the ange ring 38. The tubes 41 may be lixed against lateral ymovement by the provision of suitable `connections 54 arranged as needed along the length of the tubes il to maintain them in proper space relation as shown in FIGURE 5.

For the lubrication of the bearings in the structure 44 a suitable connection 55 is provided; any suitable lubricant may be employed. Similarly, the upper bearing structure Si) may be lubricated through a suitable connection 56.

Any suitable means may be provided for driving the shaft 4S and the impeller 46. Suitably, the power necessary may be applied through gear reducing means which are assembled in the housing 5S and which are in turn driven by a suitable turbine or motor, not shown, but

connected to the gear reducing means at 59. The gear reducing means is in each case connected to its respective shaft i8 by means of coupling means 57. The housing 56 is supported `on a pedestal structure 6i) which is bolted to the flange ring 33. The driving turbine and the gear reducing means 4d may be substituted by an electric motor.

, The settling zone 12 is divided by the partition 39 into acid section 62 and product section 6l. The partition 3i) is approximately semi-circular in shape and united to the walls of the reactor lil, as by welding. The top edge ot the partition Si) is at a somewhat higher level than the top edge of the opposed perforated plate 32 of the coalizer 29. Thereacted material as it passes through the coalizer 29 separates into acid and liquid hydrocarbon and layer separation of the two takes place in the acid section 52. The lighter liquid hydrocarbon being the top layer, overilows partition 30 and collects in the product section 6l while the acid settles in the bottom of the acid Vsection d2. The liquid hydrocarbon product is removed through the pipenozzle 63 in the bottom of the 'product section 6ft for further processing. The acid is removed through the pipe nozzle 64 in the bottom of the acid section 62.

Each section l5, le, i7, di and 62 is provided with a manhole 65 to render said sections accessible for inspection and repair. Each manhole 65 is closed by a suitable cover, as shown, during operation of the reactor il?. The sections i5, l5, and i7 are also each provided with nozzle 66 to facilitate the removal of residual material from the respective sections during cleaning, etc. The section i4 is provided with a nozzle 67 through which the isoparaiiin hydrocarbon may be introduced into the system. Section iai as well as sections i5, lo and i7 are each provided with a nozzle 62. The nozzles 68 may be manifolded through suitably valved lines, as shown for instance in FGURE 6, so that the tops of the sections 14, 15,*16 and i7 are placed in communication for gas flow at controlled rates from the sections 1d, l5 and le into the section i7 and consequently into the Zone l2. By suitable control of the gas liow out of sections 14, i5 and 16, these sections may be maintained under any preferred pressure arrangement, however, the pressures in the sections li, i5 and Sie should progressively diminish but all must always be higher than the pressure in section 17 so that the pressure diderential will be effective to facilitate the series i'low of the reactants through the sections 14, l5, le and E7 and particularly so that the light reactants will iiow in the acid catalyst or the emulsion phase.

The settling zone l2 includes the nozzles 69 for conducting gas from said section, as for instance to a cornpresser of a rerigerating system. The section 12 furthermore includes a nozzle iti through which may be returned to the settling zone i2 any liquid material, particularly any acid, carried out by the gas stream issuing from the nozzle d. A pipe extends from the nozzle 7? to assure the return of the material to the'acid section .i2 and beneath the liquid levei therein. Section 15 also includes a nozzle 7l through which the acid catalyst is supplied to the reactor it).

The reactor it? may be variously modied without departing from the invention. Thus, in place of the specific type `of mixing means shown and described, other suitable types may be used. Also, reaction zones each including two or more mixing sections and a settling section, may be disposed on each side of a single product zone and all three zones included in a single vessel. y l

In summary of the above discussion, the present apparatus for reacting liquid compounds-comprises essentially a reaction chamber defined by wall means, for example partitions i9, 22 and reactor wall it) in FIGURE l; a mixing device positioned in said chamber havinga liquid inlet Vand liquid outlet such as inlet 36 and outlet 53 in FIGURE 4, the mixing device adapted for directing liquid through a ow path sequentially upwardly and down- -7 i wardly around a centrally disposed restriction withinsaid chamber suchvas shell 39 andl impeller housingAZ in FIGURE 4 and means for representing the liquid to the inlet of the mixer which means is illustrated'in FIGURE 4 by impeller 46. The liquid which reacts with the circulatng bodyof liquid can be transversely introduced into the flow path thereof, for example by means of port feed required land not supplied bythe alkylating hydro-v carbon feed, after'having the recycle acid catalyst added to its is introduced into the entrance section 14 through Ythe nozzle 67, while the fresh'acid catalyst feed is intro-l i duced into the bottom of section 15 and beneath the hole.

'25 in the plate 24 through the nozzle 71. The isoparalln hydrocarbon feed mayv comprise a single isoparan hydrocarbon or a mixture of such'hydrocarbons or a mixture comprising one or more isoparafin hydrocarbons and onev or more normal paratiin hydrocarbons. Alternately the section 14 may be eliminated and the isoparafin hydrov carbon feed as defined above and without the addition of Y the acid catalyst recycle, supplied directly to the inlet ofV the mixer 35 through the nozzle connection 71 while the recycle acid catalyst and the fresh acid catalyst after being joined are supplied to the bottom of the section 15 through the nozzle 66. It is also possible, ythough not preferable, when the section4 14 is elimina-ted, to locate the nozzle 67 on the axis of the mixer 35 and the nozzle 71 adjacent thereto and beneath the plate 24 so that the isoparaflin and the acid catalyst enter the reactor 1! at substantially the. same location at they bottom entrance to the mixing sec# tion 15.

The alkylating hydrocarbon feed which may be a single olefin hydrocarbon, or a mixture of olefin hydrocarbons, or a .mixture of one or more olefin hydrocarbons and one or more isoparain hydrocarbons which may also include -oneor more normal paraffin hydrocarbons is divided into three separate parallel streams and a separate stream enters each'of the mixers 35, 35(a) and 35(b) through the respective nozzles 51.` The isoparan hydrocarbon content of the alkylating hydrocarbon feed may be less than, or equal to, or more than, the quantity required for alkylation reaction with all of the olefin hydrocarbon present. The alkylating'hydrocarbon feedintroduced into the nozzle 51 will flow downward through the tubular member 52 to exit out of the ports 4S at the outlet of the impeller 46 to be .admixed thereat with the Vacid catalyst and isohydrocarbon feed pumped by the impeller blades 47. 'The impeller 46 is operated at relatively high speeds Vin a manner to impart high velocity to the liquid ypresented to it so ,that it rapidly and intimately intermixes the acid catalyst, the isohydrocarbon, and the alkylating hydrocarbon andv form therefrom an emulsion. The emulsion is further formed or maintained by the high velocity. ow thereof through the tubes 41, by the rapid change in direction in the space above kthe tubes 41 and the flow through the comparatively restricted passages between the tubes 41, the shell 39 and the .tubular member 52. The flow of the emulsion at high velocity and in the manner described, produces shearing effects 'whereby the droplets of the emulsion, which ordinarily contain the isoparatfin reactants, are continuously subdivided to present new surfacesV for reaction andrto present 8y sults inV the frequent replacement of the layer vof acid catalyst immediately adjacentV the dropletsthat contain the reactants. The capacity ofthe impeller l46 is greatly in excess of that required merely to pump the acid catalyst,

the isohyd'roearbon and the alkylating hydrocarbon supplied through the nozzles 71 and 67 and theports d5y respectively through its respective mixing secti'onso that. a rapid` recirculation of the emulsion within its respective mixing section takes placeand the mixers 35,`35(a) and 35(5) are i positioned sufciently above the respectiveplates Z4, 2d' or 24 to facilitate the recirculation ac-- tion. Ihe capacity of each of the mixers 35, 35(a) and 35 (b) is l:surchthat material presented to each of them isv recirculated fifteen, orV more, times before itleaves'the respective, reaction section 15, 16 or 17.

By maintaining a proper pressure relation between the sections 14, 15,16 and `17, 'the emulsion overflows the baille '22 insection 15Qto flow downward through'the` passageway 2S and into the passageway 20', from thence to flow throughthe hole 25' andto be presented to the,

mixer 35(11) at a rate ysubstantially equal to the combined rate ofv acid Vcatalyst and hydrocarbon input. The

mixing and recirculation action is repeated in mixing section 16 but with the admixture of a fresh supply of alkylat' ing hydrocarbon, and again yemulsion flows over the Weir 2,2 to the hole 25 andfto .the bottom of the mixing section 17 at a rate substantially equal to the combinedrate f In the mix-v ing section 17, the mixing and circulating Vaction is again v repeated and again with admixture of a fresh supply of of the acid catalyst andhydrocarbon input.

alkylating hydrocarbon.`

The mixing section 17 is in open communication with the settling zone 12 and at the same pressure las the settlingzone 12, hence How of materialfrom the mixing section 17 to the acid section 62 does not take place be'- cause of a difference in static pressure butl rather be- To this end,`acid cause of different pressure heads. catalyst and product are drawn olf through nozzles 64 and 63 respectively, at such rates as to maintain the liquid level in the product section 61 below the liquid level in v the acid section 62. and the liquid level in the acid sec,- tion 62 below they emulsion level in the mixing section 17.

The top of the deilector baille 13 is at such a level as to prevent normal as well as accidentalflow of the emulsion in the mixing section 17 thereover.

The emulsion leaves the mixing section 17 over the top of the Weir partition 31 and flows through the coalizer 29 for liow into the acid section 62 of theisettling section 12.k

In owingthrough the coalizer 29, the emulsion is broken down into two continuousV phases. the lighter hydrocarbon separates as a layer on the heavier acid catalyst to overflow the partition 30 into the .prod-I uct section 61 wherefrom it is withdrawn through the nozzle 63 for further processing. The acid which collects in the bottom of the section 62 is withdrawn'in partpfor= recirculation and in part for reconditioning.

The reaction described is exotherrnic and in order to maintain the desired temperature range, the sections14, 15, 16, and 17 and the zonelZ` must be cooled. The i necessary cooling effect maybe obtained in various ways as by employing variousde'vices, such as coils through which a cooling medium is circulated, etc. The reaction and the apparatus used in carrying it out are such, how VVever, fthat vauto-refrigeration is ideally suited.,. The isohydrocarbon input is vaporized inthe various sections mentioned at suflicient rates at the operating pressures to produce a refrigeration effect* suicient to maintainzthe troducing the, alkylating hydrocarbon feed to the mixers 35, `3501) and 35(b) is particularly advantageous. For example, in the alkylation of isoparaflin hydrocarbons In the acid section 62,

9 with olefin hydrocarbons under conditions 'of temperature and pressure permitting continuous vaporization of unreacted hydrocarbons for temperature control purposes, it is particularly advantageous to introduce the olefin reactants at the outlet or high pressure side of the irnpeller 46. In view of the relatively low concentration of oleiins maintained in the reactor 10 as a whole, it is evident that the alkylation reaction, andthe development of exothermic heat of reaction, are most intense at the point Where the olefin reactants are admixed with the isoparaflins and the acid catalyst. The vaporization of the mixture at that point, therefore, is relatively high. Consequently, the introduction of the olefin feed through the ports 45 into the high pressure side of impeller 46 has the advantage of` permitting vaporization Without interfering with circulation. The introduction of the fresh feed in this manner also accomplishes substantially instantaneous and complete mixing of the olefin yreactants with the acid and the isoparaflins discharged from the impeller and the resulting mixture is then immediately driven through the tubes 41 to promote intimate `and effective contact of reactants and catalyst. Furthermore, since each impeller 46 is arranged to recirculate the acid catalyst and the isoparafiin content of its respective mixing section many times past the ports 45 through which the olen reactants are supplied, this results in effect in multiplying the ratio of isoparafin hydrocarbon to olefin hydrocarbon many times. Thus, if the ratio of isoparain hydrocarbon to olefin hydrocarbon supplied to the reactor 10 is in the order of about 4:1, the ratio for each mixing section will be about 10:1. If each impeller 46 recirculates the content of its respective mixing chamber to 40 times the mentioned ratio is increased t-o the order of 150 to 400 to l. The olefin hydrocarbons are thus immediately upon introduction into the reaction zone, subyfrom the body of liquids in the reaction zone'y by indirect heat exchange with an external refrigerating means. Preferably, however, internal refrigeration is edected by permitting continuous evaporation of unreacted hydrocarbons which are withdrawn from the mixing sections, condensed, cooled, and returned for further treatment. Isobutane available for charge material to an alkylation process ordinarily occurs in mixtures which contain substantial quantities of normal butane. A substantial proportion of propane also may be present. inasmuch as these hydrocarbons, together with the isobutane, constitute the lowest boiling constituents in this portion of the reaction mixture which are heated by the exothermic reaction, refrigerating the reaction mixture by evaporation results in the separation from the reaction mixture of vaporized hydrocarbons consisting of isobutane, normal butane and propane and predominating in isobutane. Such a mixtureis condensed and returned to the reaction zone 11. Suitably all or a portion thereof may be fractionated to separate propane to be discarded. This method of eliminating propane is advantageous because the mixture thus treated has a higher concentration of propane than any other hydrocarbon mixture in the system. Sufficient propane is thus eliminated to balance the amount introduced into the system as fresh feed.

The Vquantity of propane maintained in the reaction zone 11 may be regulated to provide the degree of evaporation necessary to abstract the heat of reaction at the conditions of temperature and pressure at which it is desired to conduct the reaction.

The schematic showing of FIGURE 6 indicates how the to 5 is hooked up in a catalyst installation. in FIGURE 6, the arrangements employed for preparation of the-various feeds, the treatment of the acid` catalyst and the treatment of the product have been omitted as such arrangethe upper portions thereof by a piping arrangement which f interconnects the nozzles 68 of the respective sections. The piping arrangement includes suitable valving adjacent each of the nozzles 66 so that the flow out of the individual sections may be independently controlled and any predetermined pressure pattern established and maintained. The nozzle 69 at the product end of the settling zone 12. is connected through suitable piping to the refrigeration system. This system includes a pump which withdraws vapor through the nozzle 69, compresses them,

and then passes them to a heat exchanger wherein they are condensed and from whence they are passed to a collection drum. A portion of the condensed gases is returned to the reactor 10 through the isobutane recycle line while the remainder is passed to the depropanizer whereat propa e is removed to balance the am-ount added to the system by the fresh hydrocarbon feed or feeds. After depropanization, the stream is returned to isobutane recycle feed and passed by suitable piping to the nozzle 67 for admission to the entrance section 14. The refrig- Y eration system includes a drum, between the nozzle 6? and the pump, in which any liquid carried over by the vapors is collected and returned to the nozzle 70 and the pipe attached thereto for injection below the liquid level in the acid section 62. The alkylating feed is divided into three streams and conducted to the nozzles 51. VAcid is withdrawn through the nozzle 64. A portion of the Withdrawn acid is removed fr-orn the system as spent acid while another portion is returned as recycle acid with the isobutane recycle. Fresh acid feed is introduced to the section 1.5 through the nozzle '71. The product is removed from the product section 6l through the nozzle 63 and conducted through suitable piping to the product treatingr system.

In the alkylation of isobutane with butenes, or propylenes, or amyle'nes, or a mixture of two or more of these oleiins, the olefin feed is divided, as shown in FlG- URE 6, into three more or less equal streams and passed to the mixers 35, 3(a) and 35(b). The olen feed usually readily available 'in a refinery for the alkylation of isobutane, includes both paraffin and olefin hydrocarbons,

and of the paraffin hydrocarbons, both the iso and the normal forms; the hydrocarbons in the olefin feed range from C2 to C5 with the olefin content generally made up of propylene and butene, isobutane is 'the only isohydrocarbon present. The isobutane content of the olefin feed usually approximates that required to react with all of the olefin hydrocarbons present. Thus, the isobutane feed is largely a recycle feed and is provided in such quantity as to maintain a preestablished isobutane to oleiin ratio. This ratio is usually in the order of 10:1 in individual mixing chambers, in accordance with the present invention isobutane to olefin ratios inthe order of 8:1 for the individual mixing sections and inthe order of 3:1 for the whole reactor lil are preferred. The isobutane feed usually readily available in a refinery contains a mixture of normal and isoparaftin hydrocarbons ranging from ethane to pentane and including propane and normal butane in substantial proportions.V The acid catalyst may be supplied at rates to maintain an acidto hydrocarbon ratio of as low as 1:1 but higher ratios in the order of 2:1 are preferred and can efficiently be handled in the method of the present invention.

The isobutane recycle, the olefin feed, the fresh acid and the recycle acid are introduced into the system and serially passed through the mixers 3S, 35(11) and 35(1)) to form an emulsion and to promote the alkylation reaction, as `described heretofore. The action inthe mixersl 35 to 35m) and 35(5) circulate the content of their rrespective mixing' sections past the respective olefin feed inlet aty such speed as in'e'ect to increase the ratio of I isobutane to olefin to the order of 150:1 and more, so that the reaction ytakes place with a minimum formation of objectionable compounds due yto hydropolymerizationi The lighter constituents of the isobutane recycle Y:feed vaporizein the sections 14,715, 16 and 17 to cool the content ofthe respective sections and to maintain a pre-established loW temperature, usually 35 F. By adjustment of the valve means in the piping through which the vapors iiow out ofthe sections 14,Y 15, and 16, desired pressures may be maintained in the respective mixing sections. Thus by way of example, the valving may be set tomaintain'a pressurev of 8 p.s.i. in the section 14, a pressure of e.

7 p.s.i. in the-section 15, a pressure of 6 p.s.i. in the section 16, and a pressure of p.s.i. in the section 17 and the settling zone 12.

The vapor withdrawn from the sections 14, 15, 16'and 17 is compressed and then condensed. A portion of the condensed vapors is returned to the system with the isobutane feed while the remainder is` passedrto the depropanizer for removal of propane as required to balance the input-of propane through the olen feed. After deptopanization said remainder is returned to `the isobutane recycle. Fresh acid is added to the system at a sulicient rate to maintain the required catalyst activity, a corresponding amount of acid is withdrawn fromthe'system as spent acid while a portion is withdrawn `for recycle. YThe.

day of alkylate product. For this quantity of product, the

olen feed employed was 3044 barrels per day madey up of:

Hydrocarbon: Barrels per day Ethane 4 Propylene 156 Propane 504 Isobutane 1135 Butene 830 Normaly butane 401 Pentanc 14 The isobutane recycle was 9198 barrels per day made up of Hydrocarbon: Barrels per day Ethane 3 Propane 841 IsobutaneV 7485 Normal butane 852 Pentane 17 The fresh acid feed was 133 barrels per day; 160 barrels per day of acid were removed from the system as spent acid while 345 barrels perday of acid were removed from the system and recirculated by admission thereofto the isobutane recycle line so as to be admitted with the isobutane recycle into section 14.y `A total of 505 barrels per day of acid were Withdrawn from the acid section 62. 5289 barrels per day were withdrawn from the production section 61. This material was made up of 1690 barrels per day of alkylate and 3599 barrels per day of material of :a composition approximating that of the sobutane recycle.

' .the temperature in the reactor was maintained `at 35 Ff To attain this temperature,.the valves inthe vapor iines Y -which connect the sections 14, 15, `and 16 to the section 17 were adjustedto maintain a pressure in the section 14 of ,They latter material was returned to the system as part of the isobutane recycle.

In operating in accordance with this specitc-example,

8 p.s.i.,.in thersection 15 of 7 p.s.i.,V inthe section 16 of 6 p.s.i.,V and insection 17 and the settling zone 12 'of 5 p1-si.y ToY handle the' refrigeration load, 6553 'barrels of liquids per dayA were=evaporated and removedfrom the settling zonelz.y The 6553v barrels per day of .condensed vapors were composed of The mixersSS, 3Std) and 35( b) were operated at such speed so that the ow therethrough past the olen feed inlet was such-as to multiply the isobutane `to olen ratio approximately twenty-five -times so `that the apparent isobutane to olefin ratio was increased to the Vorder of about 200:1 at the `point of contact withoutincreasing the isoy butane in the feed to the reactor.

The superior results obtained by the use ofthe novel apparatus Vand novelV process are apparent from` a consideration ofv the following comparative data, column `1 being data .derived from conventional practice, while column 2. being data derived from practice in accordance with the present invention.

Production (B arrels/Strearn Day) 1, 211 1, 201 Space Velocity (Volume of Acid/Volume of Oletns/Hr.) 0. 30 0, 302 Isobutane in Reactor Eluent (Liquid Volume Percent) 5l. 3 53.1 External Isobutane to Oletm' Ratio .per Mixing Section 9. 0 9. 25 Internal Isobutane to Oleiin Ratio at 2:1 Acid to Hydrocarbon Patio 149 159 Pounds `Acid Consumed/gal. Alkylate Produced 1. S9 1. 35` Spent Acid Strength Wt. Percent 94. 4 95. 2 Rerun Yield of 338 F. End Point Alkylate (Light Alkylate) B5. 7 91. 2 Octane Number F-l Clear-- Total Alkylate 92. 8` Light Alkylate 93.6 F-2 Clear- Total Allrylate 91. 3 Light Alkylate 91.8 Octane Rating Performance Number:

Y F-3+4.6 cc. TEL Light Alkylate 119 F-4+4.6 ce. TEL Light Alkylate 147 In the above F-l is .equivalent to Research Dctane Knock Rating; F-2 is equivalent to, ASTM Motor Octane Knock Rating; F-3 is equivalent to Lean Mixture Method Knock-Rating forgavi'ation gasolines; and F-4 is equiva-v lent to Rich'Mixture Method Knock Ratings for aviation gasolines. f

Since many changes may be made' withoutfdeparting from the scope of the invention herein involved,`it is intended that all matter contained in thefabove description or shown in the accompanying drawings shall beinterpreted as illustrative and not limiting to the scope of the invention. l

Having thus described our invention we claim:

1. An apparatus for effecting yliquid phaseI reactions which comprises wall means defining a mixingv section adapted to contain a body of liquid therein; inlet means and outlet means in said sectionyliquid level establishing f means vertically disposed as a Weir plate in said section; a vertically rdisposed mixing device enclosedby a mixer tributing members above said impeller adapted for introducing a second liquid into the iirst liquid iiowing upwardly past the horizontally disposed distributing members, a vertically disposed second liquid introducing means Iadapted to introduce said second liquid into said distributing members in said mixing device, a plurality of vertically elongated take-off tubes having entrance openings above said liquid distributing members, the opposite ends thereof being in open communication with the interior of said housing, said mixer adapted to induce the upward ow of a iirst liquid past said impeller and distributing members for contact with said second liquid, and to pass the resulting liquid mixture upwardly through said take-oli tubes and then to reverse the flow of liquid outside of said tubes within said housing; and liquid ejecting means in the lower portion of said housing below the upper end of the weir plate in open communication with said mixer inlet in said section for ejecting liquid from said mixer into the lower portion of said section below the level of liquid therein for direct recirculation of said liquid into said mixing device.

2. The apparatus of claim l wherein the second liquid introducing means is positioned vertically and centrally in the mixer housing.

3. An apparatus for eiecting liquid phase reactions which comprises: wall means deiining a reaction section adapted to contain a body of liquid therein; a liquid level establishing means vertically disposed as a weir plate in said section; an internally disposed mixing device within said section; a mixer housing enclosing said mixing device within said section and having inlet means in the lower portion of said section formed bythe mouth of said housing; said mixing device comprising means adapted for passing a liquid upwardly therethrough, and means adapted for reversing the flow of said liquid inside of said mixer housing, said mixer housing having liquid venting means below the upper end of said Weir plate in open communication with the mouth of the mixing device in said section and adapted to allow exit of downwardly iiowing liquid from said housing at a point below the liquid level in said section for at least partial recirculation of said liquid upwardly through said mixing device.

4. An apparatus for effecting liquid phase reactions which comprises: wall means defining a reaction section adapted to contain a body of liquid therein; a liquid level establishing means vertically disposed as a weir plate in said section; a vertically disposed mixing device and a mixer housing enclosing said mixing device Within said section and having an inlet to said mixer in the lower portion of said section formed by the mouth of said housing, said mixing device comprising an impeller, liquid distributing means above said impeller, and a vertically elongated passageway having an entrance opening above said liquid distributing means and the opposite end thereof being in open communication with the interior of said housing, said mixing device adapted to induce the flow of a liquid upwardly therethrough and to reverse the flow of said liquid inside of said mixer housing after passage through said elongated passageway; and liquid venting means in said mixer housing below the upper end of said Weir plate in open communication with the mouth of the mixing device in said section and adapted to allow exit of downwardly flowing liquid from said housing at a point below the liquid level in said section for at least partial direct recirculation of said liquid through said mixing device before liquid is withdrawn from said section.

5. The apparatus of claim 3 wherein said means for separately introducing reactant is adapted to disperse said reactant transversely across the liow path of said moving body of liquid.

6. An apparatus for effecting liquid phase reactions which comprises: wall means defining `a mixing section adapted to contain a body of liquid therein; inlet means and outlet means in said section disposed at opposite ends thereof; liquid level establishing means vertically disposed as a weir plate in said section; a vertically disposed mixing device enclosed by a mixer housing within said section and having an inlet to the mixer in the lower portion of said section formed by the mouth of said housing, said mixing device comprising an impeller, liquid distributing means above said impeller adapted for introducing of second liquid into a first liquid owing upwardly past the distributing means, and a vertically elongated take-oli tube having an entrance opening above said liquid distributing means, the opposite end thereof being in open communication with the interior of said housing; said mixing means adapted for upward ow of a iirst liquid into said mixer past said impeller and distributing means for contact with a second liquid, passage of the resulting liquid mixture upwardly through said take-olf tube andy reversal of the direction of flow of said liquid mixture outside of said tube within said housing;,liquid venting means in said mixer housing and positioned above the entrance of said take-off tube and below the upper end of? the weir plate in open communication with the mouth of the housing and adapted to allow exit of liquid from said housing yat a point below the liquid level in said section for direct recirculation of at least a major portion of said liquid through said mixing device before said liquid is withdrawn from said section.

References Cited in the iile of this patent UNITED STATES PATENTS 2,263,534 Aldridge Nov. 18, 1941 2,852,581 Stiles Sept. 16, 1958 2,927,009 Stiles et al. Mar. l, 1960 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,170, 769 February 23, 1965 Samuel R. Stiles et ale lIt is hereby certified that errorr appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant, lines 3 and 4, and in the heading to the printed specification, lines 5 and 6, for "assignorsJ by mesne assignments, to Pullman Incorporated, a corporation 0f Delaware", each occurrence, read assignors to Pullman Incorporated, a corporation of Delaware Signed and sealed this 7th day of June 1966.

(SEAL) Attest:

ERNEST WQ SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. AN APPARATUS FOR EFFECTING LIQUID PHASE REACTIONS WHICH COMPRISES WALL MEANS DEFINING AMIXING SECTION ADAPTED TO CONTAIN A BODY OF LUQID THEREIN; INLET MEANS AND OUTLET MEANS IN SAID SECTION; LIQUID LEVEL ESTAABLISHING MEANS VERTICALLY DISPOSED AS A WEIR PLATE IN SAID SECTION; A VERTICALLY DISPOSED MIXING DEVICE ENCLOSED BY A MIXER HOUSING WITHIN SAID SECTION AND HAVING AN INLET TO SAID MIXER FORMED BY THE LOWER PORTION OF SAID HOUSING FOR INTRODUCING A FIRST LIQUID FROM THE LOWER PORTION OF SAID SECTION TO THE LOWER PORTION OF SAID MIXER, SAID MIXING DEVICE COMPRISING AN IMPELLER, HORIZONTALLY DISPOSED DISTRIBUTING MEMBERS ABOVE SAID IMPELLER ADAPTED FOR INTRODUCING A SECOND LIUQID INTO THE IFRST LIQUID FLOWING UPWARDLY PAST THE HORIZONTALLY DISPOSED DISTRIBUTING MEMBERS A VERTICALLY DISPOSED SECOND LIQUID INTRODUCING MEANS ADAPTED TO INTRODUCE SAID SECOND LIQUID INTO SAID DISTRIBUTING MEMBERS IN SAID MIXING DEVICE, A PLURALITY OF VERTICALLY ELONGATED TAKE-OFF TUBES HAVING ENTRANCE OPENINGS ABOVE SAID LIQUID DISTRIBUTING MEMBERS, THE OPPOSITE ENDS THEREOF BEING IN OPEN COMMUNICATION WITH THE INTERIOR OF SAID HOUSING, SAIDMIXER ADAPTED TO INDUCE THE UPWARD FLOW OF A FIRST LIQUID PAST SAID IMPELLER AND DISTRIBUTING MEMBERS FOR CONTACT WITH SAID SECOND LIQUID, AND TO PASS THE RESULTING LIQUID MIXTURE UPWARDLY THROUGH SAID TAKE-OFF TUBES AND TEHN TO REVERSE THE FLOW OF LIQUID OUTSIDE OF SAID TUBES WITHIN SAID HOUSING; AND LIUQID EJECTING MEANS IN THELOWER PORTION OF SAID HOUSING BELOW THE UPPER END OF THE WEIR PLATE IN OPEN COMMUNICATION WITH SAID MIXER INLET INSAID SECTION FOR EJECTING LIQUID FROM SAID MIXER INTO THE LOWER PORTION OF SAID SECTION BELOW THE LEVEL OF LIQUID THEREIN FOR DIRECT RECIRCULATION OF SAID LIQUID INTO SAID MIXING DEVICE. 